Meet Kurt Russell's 'Guardians of the Galaxy Vol. 2' Character Ego, and Comics' Other Living Planets

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The actor will play Marvel's talking planet, but he's far from the only thinking world out there.

The secret is out: Kurt Russell won't just be a star of next year's Guardians of the Galaxy Vol. 2 — he'll be an entire planet, with director James Gunn revealing at San Diego Comic-Con that the actor will be playing Ego the Living Planet in the follow-up to the 2014 Marvel sci-fi hit.

This doesn't mean that Russell will be spending the entire movie as a CGI celestial body, however; in footage shared in Hall H, he appeared in human form (His costume was shown on the convention floor Sunday, and confirmed to all that the movie Ego will look like a person for at least part of the feature).

In comic books, however, Ego lives up to his billing as a Living Planet … and he's not the only one. Here's a quick guide to which planets could hold a conversation with each other during a particularly quiet cosmic event.

Ego the Living Planet

Created by Stan Lee and Jack Kirby for 1966's Thor No. 132, Ego isn't just a planet that's able to talk — he's an evil planet that's able to talk. He started out as a regular alien scientist who became merged with his home world in a freak accident, and decided to make lemonade out of those particularly unfortunate lemons, by conquering the other planets around him. After all, they couldn't think for themselves, or even talk. As should only be expected, he was eventually joined by a sentient moon called "Id the Selfish Moon." This, impressively, is honestly true; Id debuted in 2011's Deadpool No. 23.

Kathulos of the Eternal Lives

Debuting in 1973's Marvel Premiere No. 8, Kathulos brought a twist to the Living Planet idea by being a Lovecraftian monster planet that served the demon Shuma-Gorath. As far as servants go, Kathulos was a pretty useful one, able to not only serve Shuma-Gorath itself, but also send creatures from his surface out to do his bidding as well. Luckily, whatever threat he posed was ended by the magical powers of Doctor Strange.

Pandarve

Alternatively known as the Jewel of the Universe, the Red Planet and — of course — the Living Planet, Pandarve is not only the setting for Don Lawrence's European sci-fi/fantasy series Storm, but also one of its characters — a being that traditionally communicates through a chosen servant, but has the ability to create a human form if she so wishes. Yes, unlike the other living planets, Pandarve identifies as female; of course, quite why any planet should choose a particular gender seems somewhat nonsensical.

Mogo

The literal centerpiece of DC Entertainment's Green Lantern mythology, Mogo — a living planet that also happens to be part of the intergalactic Green Lantern police force — nowadays acts as the headquarters of the Green Lantern Corps and home to its founders, the Guardians of the Universe. That's a big change from his first appearance, in a 1985 story from Green Lantern No. 188 by Alan Moore and Dave Gibbons that focused on his loneliness, titled "Mogo Doesn't Socialize."

Unicron

A year after the introduction of Mojo, the 1986 animated Transformers: The Movie brought in the ultimate threat to the shapeshifting mechs: a robot that turns into a planet that eats other planets. As if that wasn't enough, Unicron had one more reason to turn his foes into quivering wrecks: He was voiced by none other than Orson Welles in his final screen role. Unicron would go on to show up in subsequent animated series and comic books set in the Transformers franchise for decades following, forever making all other robots look lazy in their choice of alter ego.